EXPERIMENTAL STUDY ON DAM-BREAK FLOOD WAVES OVER MOVABLE BED CHANNEL
摘要
This paper presents the results of an experimental study focused on the propagation of dam-break flow waves over movable beds.Tests consisted in the sudden opening of a vertical lift-gate which separated initial water and sediment levels upstream and downstream of the gate.They allowed the simulation of the following initial conditions: with or without initial bed-step at the gate cross-section; with or without water downstream of the gate; with or without sediments downstream of the gate.Test results were used to discuss the influence of the movable bed on the celerity of the wave-fronts,as well as on the downstream wave-front height.The total volume of dislodged sediments was also assessed.Some important conclusions were achieved: i) the movable bed does not affect the upstream wave-front celerity but it affects the celerity of the downstream wave-front; ii) the experimental celerities show some disagreement with the analytical solutions; iii) the existence of an initial bed-step at the lift-gate cross-section influences the downstream wave-front propagation,including the water depth.